Nevado Del Ruiz , Colombia :

Weekly activity bulletin of the volcano Nevado del Ruiz, from April 11 to April 17, 2017The level of activity continues: at the level of yellow activity or (III): changes in the behavior of the volcanic activity.

As regards the monitoring of the activity of the Nevado del Ruiz volcano, the Colombian Geological Survey reports that:

Over the past week, the various monitoring parameters show that the Nevado del Ruiz volcano continues to show unstable behavior.

The seismicity caused by fracturing of the volcanic rock, recorded a slight increase in the number of recorded earthquakes as well as seismic energy released compared to the previous week. This seismicity was mainly found in the Northeast zone and to a lesser extent in the South-East zones and the Arenas crater. The depths of the earthquakes range from 0.3 to 7.4 km. The maximum magnitude recorded during the week was 1.7 ML (local magnitude) for the earthquake of 13 April at 09:38 (local time), 2.2 km northeast of the Arenas crater, at a depth of 3.8 km. The last week saw the occurrence of short-lived Drumbeat seismic events and low energy levels, which were recorded on 13 April, from 8:55 to 9:05 (local time) . This type of seismicity is related to the growth processes of domes (1) at the surface.

[1] dome of lava: a mound of lava (molten rock) viscous that places itself on the emission duct of a volcano. The growth rate of domes can vary from a few hours to a few days, years, even hundreds of years, and volumes can reach tens of meters to several cubic kilometers

With regard to the seismic activity associated with fluid dynamics in the ducts of the volcanic structure, it showed an increase in energy levels. This type of activity is mainly characterized by the presence of several fluid earthquakes, long-period events and tremors pulses, with varying energy levels and durations. Some of these seismic signals have been associated with emissions of gases and ash into the atmosphere, as confirmed by the images captured by the cameras installed in the volcano area and by reports from Los Nevados National Park officials and of the Colombian Geological Survey who were working on the ground. Recordings of seismic signals of this type are not excluded with higher energy levels which may be associated with emissions of gas and ash. It is important to remember that the ash emission processes can occur for several days and sometimes several times during the day, without involving an individual report for each episode.

Volcanic deformation, measured from electronic inclinometers, Global Navigation Satellite Systems (GNSS) and satellite images to determine changes in tilt, position and shape of the volcano, continues to record In recent months a deflationary process and intermittent inflation / deflationary impulses, possibly linked to gas and ash emissions.

The volcano continues to emit large amounts of water vapor and gases, including sulfur dioxide (SO2), as shown by the values ​​obtained by the SCANDOAS stations installed in the volcanic analysis zone And satellite images. In the tracking information provided by the FIRMS portal Mírová, NASA, a low-energy thermal anomaly was identified on April 11th. The columns of gas, steam and ash from time to time reached a maximum height of 2200 m measured on the top of the volcano on 11 April. The direction of dispersal of the column was in line with the direction of the wind in the area, which predominated during the week to the northwest of the volcano.

The volcano Nevado del Ruiz continues to activity level Amarillo.

Source :SGC

Photos : Archives SGC, Cesar Rios .

Nishinoshima , Japan :

New activity on Nishinoshima.

The eruption was spotted by a Japanese Coast Guard aircraft at 14:25 local time on April 20, prompting the authorities to issue a warning to nearby ships.
It was observed a whitish plume rising from the crater of the center of the island and it was confirmed the spread of ashes. In addition, a new 300 m lava flow was confirmed. According to the Tokyo VAAC, the ash column reached 2.4 km altitude but was not visible in the satellite images.

In addition, the Japan Meteorological Agency (JMA), following analysis of data sent by satellite, found that on April 19, the temperature was high on Nishinoshima.For this reason, and in anticipation of the continuation of the eruption, the Japan Meteorological Agency issued a peripheral alarm around the crater in an area of approximately 1.5 km and the Coast Guard launched an alert to navigation.

The island of Nishinoshima in the Ogasawara islands in Japan erupted in November 2013 and has been erupting continuously until November 2015. The island already existed due to an eruption in 1973 but after two years of Crisis, the previous island was virtually covered and also increased by 12 times its original size.

The satellite images taken on April 19, 2017 show the eruption of Nishinoshima

Professor Kenji Nogami of the Tokyo Institute of Technology, following a video analysis of the Japanese Coast Guard, explained that since the crater in the center of the island a stream of lava has been emitted. It also explains that the lava flows in large quantities and it is possible that it reaches the coast and increases the size of the island.

Source :Japan Times

Photo : Japan Coast Guard

Katla , Iceland :

Katla sends « uncomfortable » earthquakes

19 APRIL 2017. The Katla volcano was recorded the issuance of two earthquakes on the morning of the 19th, both measuring more than M3 on the Richter scale. Small replicas followed these two earthquakes.

Kristín Jónsdóttir, a geologist from the Icelandic Met Bureau, told RÚV that he was « never comfortable » when tremors of more than M3 years are recorded on the volcano. These tremors are not related to any geothermal activity, but come from the center of the caldera.

The Katla will continue to be monitored closely for any new activity.

The volcano showed considerable activity last summer, but has been virtually silent this year so far. The Science Advisory Board of the Department of Emergency Preparedness and Emergency Management now believes that an eruption is more likely than ever before.

However, keep in mind that not all eruptions are equal. As things stand, there is a 45% chance that in the event of a rash, it will be small. There is a 25% chance of a medium to large eruption, and only a 5% chance of a catastrophic Katla eruption. So even if the volcano erupts – and science can never predict when it will happen – it is likely that it will not be devastating.

Source : REYKJAVIK GRAPEVINE

Photo :Art Bicnick

Sheveluch , Kamchatka :

Explosive-extrusive eruption of the volcano continues. Ash explosions up to 26,200-32,800 ft (8-10 km) a.s.l. could occur at any time. Ongoing activity could affect international and low-flying aircraft.

A growth of the lava dome continues (a viscous lava flow reveal in the northern its part), strong fumarole activity, ash explosions, hot avalanches and an incandescence of the dome blocks and hot avalanches accompany this process. Satellite data by KVERT showed a thermal anomaly over the lava dome on 13-17 April; ash plume and cloud drifted for about 95 km to the east from the volcano on 15 April.